Causes of Hay Fever

Hay fever affects one in four people in the UK, and is caused by an allergic reaction to pollen. Hay fever gets worse between March and September when pollen counts are at their highest.

Read on to find out more about which types of pollen could be causing your hay fever, and what you can do about it.

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What is hay fever?
What types of pollen cause hay fever?
What causes hay fever in winter?
What causes symptoms similar to hay fever?

What is Hay Fever?

Hay fever, also known as seasonal allergic rhinitis, is a type of allergy that is triggered by pollen (a fine powder produced by plants and flowers). It is most common in spring and summer when pollen levels in the air are highest.

Allergies occur when your body perceives something as a threat and releases a chemical called histamine. When the threat is real, histamine plays an important role in defending the body from things that can make us sick like viruses and bacteria.

However, in some people, the body overreacts to something that isn’t a threat at all, and histamine causes symptoms of an allergic reaction. Symptoms vary depending on what triggered the allergy and how severe the reaction is.

Hay fever is a very common allergy and affects around 16 million (one in four) people in the UK. Though it isn’t dangerous, hay fever can impact your quality of life and make you feel unwell.

Common symptoms of hay fever include:
blocked nose
itchy, watery eyes
sneezing
coughing
itchy mouth (especially the roof of the mouth), nose, throat, and ears
headache
earache
loss of smell
fatigue (feeling tired)

Hay fever is more common in people with other allergic conditions like asthma, eczema, and food allergies. The reason for this is thought to be genetic and allergies often run in families.

Hay fever is most common in children and adolescents with a steady decline in the number of people affected from age of 20 onwards.

Hay fever cases have increased rapidly in the past 30 years, likely due to a rise in global temperatures and increased pollution in large cities that has been shown to trap pollen in the air.

What types of pollen cause hay fever?

There are around 30 types of pollen that can cause hay fever, but some are more likely to trigger allergies than others. Normally the smallest, lightest pollen spores that are blown around by the wind are the most likely triggers. You may be allergic to one or several types of pollen. An allergy skin prick test can tell you which types of pollen you are allergic to and make it easier to avoid contact with that type of pollen. This test involves gently pricking the skin on your forearm and introducing a small amount of the substance you may be allergic to. If you are allergic there will be a reaction (redness, itching, and swelling of the skin on your arm) within about fifteen minutes.

The types of pollen most likely to trigger hay fever are:

tree pollen, produced by trees such as birch, cedar, and oak are common triggers for hay fever in early spring
grass pollen is the most common trigger for hay fever and usually occurs in late spring and summer
weed pollen like ragweed, sagebrush, pigweed, and tumbleweed are most common in autumn
flower pollens are less likely to trigger hay fever, but certain flowers like dahlias, sunflowers, and chrysanthemums can cause hay fever symptoms in late spring and summer

What causes hay fever in winter?

True hay fever is caused by a pollen allergy and typically occurs in late spring and summer, though it can happen as early as January and as late as September. Hay fever symptoms like coughing, runny nose, and itchy eyes in winter are unlikely to be hay fever and are probably due to another allergy (such as house dust mite allergy), or the common cold.

What causes symptoms similar to hay fever?

Some conditions and illnesses have similar symptoms to hay fever, and it can be difficult to tell them apart. It's important to know whether your sneezing, runny eyes, and blocked nose are due to hay fever or something else to ensure you get the right treatment.

Some conditions with similar symptoms to hay fever include:

the common cold
infection of the sinuses (sinusitis)
COVID 19
dust mite allergy

Let's look at each of these conditions in turn and some ways in which you can tell them apart from hay fever.

The common cold

Whereas hay fever is caused by an allergy to pollen, the common cold is caused by a virus. Symptoms of the common cold include:

coughing

sneezing
blocked nose
runny nose and watery eyes
sore throat
headaches
pressure in your ears and face

feeling feverish

One way to differentiate between hay fever and the common cold is by looking at the colour of the mucus discharge from your nose. If you have a cold this mucus is usually yellow or green, whereas if you have hay fever, it will usually be clear. Another difference is that with a common cold your eyes, nose, and throat aren’t usually itchy (though they may be sore).

Sinusitis

Sinusitis is swelling and inflammation of the sinuses ( the cavities around your nose) and usually happens due to a virus. Symptoms of sinusitis include:

pain and pressure around your eyes, cheeks, and forehead
headache
blocked or runny nose
reduced sense of smell
high temperature (fever)

Although some of the symptoms can be similar, if you have hay fever you will not have a fever and as with a common cold, the mucus discharge with hay fever is usually clear and not yellow or green.

COVID 19

Symptoms of COVID19 can vary and range from mild to severe depending on your general health, the type of variant you have, and whether or not you have been vaccinated. Common symptoms include:

fever
cough
shortness of breath or difficulty breathing
muscle pain
headache
runny nose
loss of taste or smell
sore throat

If you are unsure whether you have hay fever or COVID 19, it is best not to take any chances and to follow government guidelines in regards to testing and isolating.

Allergic rhinitis

Allergic rhinitis is another type of allergy but is triggered by something other than pollen. It normally presents with the same symptoms as hay fever. Because allergic rhinitis isn’t triggered by pollen it can occur at any time of the year. Common triggers include:

house dust mites. These are microscopic pests that live in bedding, mattresses, carpets, and furniture. Their droppings and body fragments are a common cause of allergic rhinitis
fungi, like mold and mildew, live in both indoor and outdoor environments and thrive in damp conditions. They produce spores that travel in the air and can trigger allergies in some people
animal dander is the term used to describe dead skin cells, urine, and saliva from pets.
Other allergens that can trigger allergic rhinitis include work-related allergens such as sawdust, flour, and latex

How to manage hay fever

While there is no cure for hay fever, it can be managed with medications that reduce or relieve symptoms. Common treatments for hay fever include antihistamines and nasal sprays.

Antihistamines work by blocking the actions of histamine, the chemical produced by the body in response to a perceived threat. Some antihistamines can cause drowsiness, and though there are non-drowsy antihistamines available, it’s important to make sure you are not affected before driving or operating machinery. If you experience serious side effects from taking any medication, seek medical attention immediately.

Telfast (fexofenadine hydrochloride) is a prescription-only oral antihistamine. One tablet should be swallowed whole with water once a day before food. Telfast normally starts working in around 1-3 hours. Common side effects include drowsiness, headache, nausea, and dizziness. Other brands of fexofenadine can also be bought over the counter.

Neoclarityn (desloratadine) is a prescription-only antihistamine available from Superdrug Online Doctor. It is taken as a tablet once a day with water and can be taken with or without food. Common side effects of neoclarityn include fatigue, dry mouth, and headaches.

Nasonex is a prescription-only nasal spray that is used to relieve symptoms of hay fever such as nasal congestion, itching, and runny nose. Nasonex contains a type of corticosteroid medication and works by reducing inflammation and swelling in the nose. It comes in a pump that is sprayed into each nostril and is normally started with two sprays into each nostril once a day. This can be reduced to one spray as symptoms improve. Other steroid nasal sprays are available over the counter.

If you are pregnant or breastfeeding, suffer from any health problems or take any other medications it’s always best to chat to the pharmacist or doctor before taking medication for hay fever.

Other treatments and precautions

In addition to taking medication, there are a few things you can do to minimise the effects of hay fever.

Stay inside when the pollen count is high (over 50 grains per cubic feet of air).
If you do go outside, wear wraparound sunglasses to reduce the amount of pollen coming into contact with your eyes.
Apply a small amount of Vaseline around your nostrils to trap pollen spores.
Change your clothes and take a shower when you get back indoors to remove any pollen on your clothes or body.
Keep doors and windows shut.
Dust and vacuum regularly.
Use a pollen filter in your car and vacuum cleaner.
Avoid cutting the grass or walking on the grass.
Don’t hang clothes outside to dry.
Don’t keep fresh flowers in the house.

If your hay fever is severe or isn’t responding to standard treatments, immunotherapy, otherwise known as hypersensitisation or desensitisation therapy may help. This is a treatment aimed at “teaching” your immune system to react less severely to allergens and works by gradually exposing your body to the allergen over time. Gradually increasing amounts of the allergen are injected into the skin of your upper arm or given orally, normally over a period of three to five years.